Engines, for example vehicle engines, are known to include aspirators or ejectors for producing vacuum and/or check valves. Typically, these components are formed from plastic that is molded, such as by injection molding techniques. Molding components is a cost effective way to manufacture the internal passageway(s) to desired geometries out of plastic material that can survive the operating conditions experienced in an engine system. These molding techniques, however, do have some shortcomings. Flash is commonly formed at the interface between the mold core pieces that form the internal passageway(s). This flash can interfere with the flow of fluid through the internal passageways, which is likely to reduce performance of the aspirators or ejectors and/or check valves. The removal of the flash from the interior of aspirators and ejectors and/or check valves needs to be accomplished in a manufacturing efficient and cost effective manner. A second shortcoming is the general difficulty in forming a corner radius on inlets and outlets of the internal passageway(s) during the molding process.
Molding techniques, such as injection molding, tend to provide a surface finish that is generally quite smooth, including those internal surfaces formed by mold core pieces. However, there may be times when a different surface finish could be beneficial, in particular could improve performance of the component.
What is needed is a method or methods that remove the flash, form a corner radius, and, optionally, modify the surface finish of internal passageways.